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"I remember one particular young woman," recalled the caseworker who works with victims of sexual trafficking. "She was brutally beaten; her skull was cracked open. She was forced to go out and work (as a prostitute) two weeks after that.

"However, she only told us about the incident a year later. That's when she could finally talk about it."

The caseworker, who requested that her name withheld, works at Tapestri, an organization in Atlanta that helps victims of sexual trafficking regain their lives after the unspeakable horrors of sexual trafficking and slavery.

"Human beings first start from a place of trust," said Allen Keller, director of the Bellevue/NYU Program for Survivors of Torture.

"That has been hard-wired since we were born. For these victims, that has been turned on its head," Keller added. "So even if they are now physically free, they are psychologically imprisoned."

Another caseworker at Tapestri, whose name is also being withheld, recounted how she had to gain the trust of a woman who had been enslaved for 10 years until she was able to escape a trafficker.

"They spend what feels like their whole life listening to the trafficker - 'Do not trust immigration, do not trust, do not trust' - and then we say, 'I'm here to help you,' and they have the 10 years in the back of their head and they look at you like, 'Sure.' They worry they will be prosecuted."

Philip Seymour Hoffman withdrew a total of $1,200 from an ATM at a supermarket near his New York City apartment the night before he was found lifeless in his bathroom with a syringe still in his left arm, sources told NBC News.

"The trafficker makes them believe he has the documents," said one of the caseworkers. "Once they are here, he tells them that they are illegal and says, 'If you don't want me to beat you or report you, you have to work as a prostitute.'"

Actions, not just wordsHow do professionals at nonprofits and immigration agencies persuade victims who have been stripped of trust to trust again?

"What makes them gain trust is action," said one of the Tapestri caseworkers. "Taking them to the doctor, helping them get clothing, counseling, English-as-a-second-language classes - whatever their immediate needs are, we help them."

Taking care of a trafficking victim's immediate physical needs is very important for their mental healing, said Keller, whose program has helped victims of torture from around the world.

"A trafficking victim who has been repeatedly raped or beaten may have real physical pain. Any time they have physical pain, even if it is not related, it triggers fear and terror, sadness and humiliation," he said.

After a trafficking victim's physical needs are addressed, immigration authorities and caseworkers then work at an even harder task - gently persuading these women to talk of their captivity. This is important for two reasons: It helps the victims, most of them undocumented, secure legal status, and it helps authorities prosecute a trafficking ring.

Taking that step is tough, said Keller, whose program trains asylum officers in effective interviewing skills.

"I've treated many individuals who were tortured in other countries. They still have profound fears and terrors, but at least their torturers are far away," he said. "For victims of sexual trafficking in the U.S., their traffickers are here and the victims are under their control."

'He was lying to you'Alia El-Sawi is a victim assistance specialist for Immigration and Customs Enforcement (ICE), Homeland Security Investigations, in the Atlanta area. She recalls how she has persuaded sex trafficking victims that much of what they have been told is simply not true.

"With some of the recent Latino trafficking victims, traffickers have used the romancing tactic," El-Sawi said. "We talk to the women about how the trafficker deceived them, was unfaithful, lied to them and forced them into heinous acts. Many of these victims then come to the realization that it's OK to be angry."

Another tactic traffickers use is the fear of immigration authorities.

"We had one young lady who had really been brainwashed by her trafficker," El-Sawi said. "He had told her U.S. immigration authorities would put her in jail and not feed her, as well as punish her and use cruelty. Once the victim saw we had taken her to the doctor and given her food and clothing, she started to trust us after a few interviews."

Caseworkers also appeal to the victims by reminding them that the traffickers are still plying their trade and that other girls and women are in danger.

"In one case, a young lady and her sister were lured into forced prostitution. The traffickers threatened to get other family members. So we homed in on how much justice she would be bringing to those other girls who could not escape," El-Sawi said.

But just as important, victim specialists spend time persuading these women that it was not their fault.

"We stress this happens in all communities across the board. We take away the piece of shame and we tell them it is not their fault, it's universal, and there are horrible people with very manipulative sides," El-Sawi said.

How long does it take for a young woman to trust the caseworkers and immigration specialists? Sometimes it takes only one or two interviews.

But El-Sawi recalled the case of a young Asian woman who was extremely reluctant to talk. "It took almost half a year before she could trust us to help her. That was one of the hardest cases," she said.

Caseworkers also say the best way to help regain the victims' trust is to tell them stories of former victims, women who received help.

"It's easier to relate to personal stories and not just facts," said one of the Tapestri caseworkers in Atlanta.

Can't undo it, but can move on"There's nothing one can do to undo the horrible things, but there is a lot we must do for individuals to get on with their lives," said Keller, who is also on the New York City mayor's Human Exploitation Working Group, whose goal is to promote appropriate services for survivors of trafficking through public/private partnerships.

"Healing doesn't mean erasing what happened, but it is gratifying to see individuals who were so brutalized be able to heal physically, socially and emotionally and gain meaningful trust in the system," he said.

In Atlanta, the two caseworkers recounted how they still talk regularly to the trafficking victims they helped heal years earlier.

"I have clients who call me two or three times a week," said one caseworker. "They will call to chat, ask for advice for themselves or their friends. They are still in a strange country."

Keller said there are challenges for caseworkers who work with trafficking victims, because "we live in a brutal world where things like trafficking and torture are all too common. When you are working with these victims, you have to watch for secondary trauma."

But he said he was constantly amazed by the resilience of the human spirit.

"Frankly, that's why I find the work gratifying. … I know with appropriate support individuals can be helped."

Although former trafficking victims and caseworkers first met under terrible circumstances, many things do heal over time.